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Some Endangered

Guenon

CLASS: Mammalia (Mammals)

ORDER: Primates

FAMILY: Cercopithecidae

GENERA: 6

SPECIES: 36

ABOUT

Cheeky fellows: Guenon (GWEN non) is the name for a group of medium-sized monkeys that have long back legs, a rounded head, a long tail that helps them balance while moving through the trees, and large cheek pouches. The word guenon comes from the French word for monkey. Monkeys in the guenon group are some of the most colorful, graceful, and lively in Africa.

Guenons are best known for their striking color patterns, such as hip stripes, brow bands, or a white nose spot or band. Facial adornments can also include a throat ruff, beard, or mustache. They use their cheek pouches to store extra food as they forage. The pouches can hold almost as much as their stomach can!

While guenons make a variety of sounds, they also communicate with several gestures and facial expressions: an open mouth showing sharp teeth, closed eyelids, or a movement of the head or tail can get different messages across to other guenons loud and clear! Yet, except for occasional grunts issued by the group leader to keep the troop together or to warn of potential danger, they are rather silent. Expressive tails, which are longer than the body, are used to indicate mood.

Spot-nosed and crowned monkeys also communicate by jerking their head in different positions, each of which mean something specific. De Brazza's monkeys use their lush, white beard for visual displays. Scientists have recorded seven different sounds Wolf's monkeys make, including a grunting call they use to keep in contact while foraging. It appears that this grunting increases when the Wolf’s monkeys are foraging for insects: could this be their favorite food?

Red-tailed monkey—friendly neighbors: Red-tailed monkeys have a white nose, a speckled, yellow-brown coat, and a long, chestnut-red tail. They can live in large groups of up to 50 monkeys, but when things get too crowded for the amount of food available, the troop may split into smaller groups.

Wolf's monkey—tufted ears and much to hear: These colorful guenons have nothing to do with a wolf: they were named after the person who first described them for science. They have a pale forehead and a black stripe above their eyes, stretching from tufted ear to tufted ear. This gives them a rather grim appearance, but they are social. Because they also feed on nectar, Wolf's monkeys serve as pollinators for certain rain forest trees.

Spot-nosed monkey—talking with tails: Furry white beards and a bright white mark on the nose make spot-nosed monkeys easy to identify. These energetic and curious guenons use their expressive tails to "talk" to others and indicate their mood.

De Brazza's monkey—colorful loners: A bit different from most other guenon species, De Brazza’s monkeys are often paired for life. Among the largest of the guenons, De Brazza's have a distinctive, beautiful coloration. Their body is grayish, with a reddish-brown back and black arms, legs, and tail. Their rump is white, and they have a white stripe on their thighs. Young De Brazza's monkeys have a yellow rump, and adult males have a bright blue rump display during mating season! Groups of De Brazza's have been known to sit completely still for up to five hours and then creep silently away into the forest.

Allen's swamp monkey—go fish: Classified as a separate guenon species, Allen’s swamp monkeys “go fishing” by laying leaves or grass on top of the water, and grabbing fish that come to hide underneath. As their name implies, swamp monkeys live near water and are good swimmers; webbed toes help them paddle through water. They have been known to dive into the water to escape predators. Allen's swamp monkeys have a sturdy build and gray/green skin. The face is reddish with long hair bundles at the cheeks.

This monkey likes company! The average group size is around 40 individuals. These large groups are divided into sub-groups of two to six monkeys that work together foraging for food. The groups' sleeping sites are usually located near water, and become regular spots and repeatedly used.

HABITAT AND DIET

Guenons come from western and central Africa, were they live in different types of forests. Like many Old World monkeys, guenons have a pad of tough skin and underlying tissue that cushions their rear end for sitting. Most guenon species are arboreal, living in the tropical forests and woodlands. But some spend a greater part of their time on the ground and are found in forested mountain areas.

Unlike other tree-dwelling and leaf-eating monkeys, guenons have a more varied diet that includes fruits, seeds, and insects. Guenons also prey on some reptiles and occasionally small mammals. Arboreal guenons travel down to the lower branches and sometimes even to the forest floor to find tasty bugs and leaves.

At the San Diego Zoo, the guenons are offered nutritionally complete primate biscuits, assorted fruits (such as apples, grapes, melons), vegetables (green beans, corn, eggplant), and greens (cabbage, lettuce, kale). These items are rotated so the guenons have different selections each day. Enrichment treats can include raisins, popcorn, and peanuts.

FAMILY LIFE

Most guenon species live in large groups of females and at least one resident male, with groups of "outsider" males drifting in and out of the territory. Sometimes males live separately or in small bachelor groups. Different guenon species often mix together. They understand each other's alarm calls and know how to react.

Guenons use loud, booming calls and bird-like chirps to alert each other. The calls vary depending on the type of predator and its location. The alarm call for the lesser spot-nosed guenon sounds like a car purring; the male “purrs” to distract the threat while his troop quietly slips away. Danger for guenons can come from chimpanzees, leopards, or eagles. Hanging out with other monkey species may help all the monkeys improve their diets and be better able to spot predators—safety in numbers!

De Brazza's live in male/female pairs. They have a large "boom" call, made even louder when they inflate their vocal sac, which they use as a warning. The males shake branches to keep a predator away and may even attack!

Guenon mothers are the main caregivers for their single infant, although other adult females in the group may assist. Guenon babies are carried by the mother, and at two weeks of age, babies are able to climb on their own. They attain their adult coloration at two to three months; the characteristic beard and mustache of De Brazza’s monkeys appear at about three weeks. De Brazza’s monkey babies grow up faster than those of other guenons; by the time they’re five months old, they’re already finding and eating their own fruit.

Guenon babies are weaned at 9 to 18 months, depending on the species. With most guenons, related females stay with each other throughout their lives; a daughter’s social status depends on her mother’s ranking in the group. Males leave their family to join a different group when they reach maturity.

AT THE ZOO

The San Diego Zoo’s primate collection began in 1923 when our founder, Dr. Harry Wegeforth, went to the East Coast and purchased pairs of several species from dealers. Our first guenons were lesser spot-nosed monkeys and Sykes monkeys received in an exchange with a German zoo in 1929, and a Schmidt’s red-tailed monkey came in 1930. L’Hoest’s and owl-faced monkeys were added to collection in 1960, with a young pair of the latter as gifts from the Leopoldville Zoo in what is now the Democratic Republic of the Congo. The San Diego Zoo was the first facility in the world to welcome a Diana monkey birth and the first in the United States to have a L’Hoest’s monkey baby.

Today, the Zoo is home to five guenon species. They can be found in various enclosures in the Zoo’s Lost Forest. Lesser spot-nosed monkey Sassy is diabetic. Trained to accept daily insulin shots, she lives with fellow lesser spot-nosed monkeys Rachel and Lester.

The rest of our guenons share their enclosures with other species. For example, Wolf’s monkey siblings Dru and Amara live with two pygmy hippos, Elgon and Francesca. Amara and Dru love to hop atop a hippo’s back for a free ride or swim underwater right alongside them, which is unusual for a monkey.

Red-tailed monkeys live with Allen’s swamp monkeys and spot-necked otters live in one enclosure, while just across the path you’ll find red-tailed monkeys and with swamp monkeys with red river hogs, a forest buffalo, and a spot-necked otter. There’s never a dull moment in these mixed-species groups!

CONSERVATION

As logging roads open a way into the forests of equatorial Africa, guenons are one of the primary targets being hunted by humans for the illegal bushmeat trade. Often, guenon mothers are killed and their babies kept as pets. Dryad monkeys Cercopithecus dryas are at critical risk, the Preuss’s monkeyCercopithecus preussiis endangered, and others are vulnerable.

Tail length: 12 to 39 inches (31 to 100 centimeters), depending on species

FUN FACTS

If you hear a guenon sneeze, it's probably the "sneeze call" that guenons pass through the group as an alarm.

The first scientific symposium devoted to guenons took place in 1985.

There are natural hybrid zones where some guenon species have been found to breed with other guenon species. More research is needed to confirm whether this has always happened or is a result of modern-day pressures caused by loss of habitat.

The lesula is the newest guenon species to be cataloged. The first individual was “discovered” by scientists in 2007.

DISCOVER WILDLIFE

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